//! 内存分配器模块
//! 
//! 提供动态内存分配功能

use crate::utils::error::{YayaError, Result};

/// 内存分配器
pub struct Allocator {
    heap_start: usize,
    heap_size: usize,
    allocated: usize,
}

impl Allocator {
    /// 创建新的内存分配器
    pub fn new(heap_start: usize, heap_size: usize) -> Result<Self, YayaError> {
        Ok(Allocator {
            heap_start,
            heap_size,
            allocated: 0,
        })
    }
    
    /// 初始化内存分配器
    pub fn init() -> Result<(), YayaError> {
        info!("初始化内存分配器");
        Ok(())
    }
    
    /// 关闭内存分配器
    pub fn shutdown() -> Result<(), YayaError> {
        info!("关闭内存分配器");
        Ok(())
    }
    
    /// 分配内存
    pub fn allocate(&mut self, size: usize, align: usize) -> Result<usize, YayaError> {
        if self.allocated + size > self.heap_size {
            return Err(YayaError::OutOfMemory);
        }
        
        let address = self.heap_start + self.allocated;
        self.allocated += size;
        
        info!("分配内存: 地址={:#x}, 大小={}", address, size);
        Ok(address)
    }
    
    /// 释放内存
    pub fn deallocate(&mut self, _address: usize, _size: usize) -> Result<(), YayaError> {
        // 简化实现：在libOS架构中，应用负责自己的内存管理
        // 实际实现需要更复杂的内存管理策略
        Ok(())
    }
    
    /// 获取已分配内存大小
    pub fn allocated_size(&self) -> usize {
        self.allocated
    }
    
    /// 获取剩余可用内存大小
    pub fn available_size(&self) -> usize {
        self.heap_size - self.allocated
    }
}

/// 获取全局内存分配器实例
pub fn get_allocator() -> &'static mut Allocator {
    static mut ALLOCATOR: Option<Allocator> = None;
    
    unsafe {
        if ALLOCATOR.is_none() {
            // 假设堆从1MB开始，大小为64MB
            ALLOCATOR = Some(Allocator::new(0x100000, 64 * 1024 * 1024).unwrap());
        }
        ALLOCATOR.as_mut().unwrap()
    }
}